1. Field of Invention
The present invention relates to a single band antenna and an antenna module.
2. Related Art
Antenna is an important element for transmitting and receiving wireless signals in the wireless products. Without it, the wireless products cannot communicate properly. Therefore, the antenna plays an essential role in wireless communication.
The rapid development of wireless communication brings various types of products and technologies applying multi-band transmission, such that many new products have functions of wireless communication so to meet consumer's demands. The current product demands are not only the basic functions but also additional functions such as GPS, Bluetooth communication, and Mobile Internet. These additional functions need to be implemented with hardware elements and the increasing number of such elements will take more space in the small-sized products. This decreases the space for the antenna in the product.
Because there are various kinds of single band antennas, an inverted-F antenna is used as an example. FIG. 1 shows a conventional inverted-F antenna 1. With reference to FIG. 1, the conventional inverted-F antenna 1 includes a radiating part 11, a feeding part 12, a grounding part 13 and an impedance matching part 14. The radiating part 11 connects the feeding part 12 with the impedance matching part 14 and the impedance matching part 14 is connected to the grounding part 13, such that the inverted-F antenna 1 is formed.
The operation of the inverted-F antenna 1 is described as follows. The signal is fed into the antenna from the feeding part 12 and generates resonance along the feeding part 12 and radiating part 11. The operating frequency band of the inverted-F antenna 1 is determined by the length of the signal resonant path from feeding part 12 to radiating part 11, and the properties of the inverted-F antenna 1 may be adjusted by the impedance matching part 14. The inverted-F antenna 1 is operated at 2.4 GHz for example, and the length L01 needs at least 45 mm to reach the required frequency band. When the operating frequency band of the inverted-F antenna 1 becomes lower, the length of the radiating part 11 has to be longer, such that the antenna takes more space and is difficult to use in the small-sized electronic products.
Thus, it is an important subject for the present invention to provide a single band antenna and an antenna module that the path for signal oscillation is extended and the size of the antenna can be effectively reduced, such that the single band antenna and the antenna module can be applied on various kinds of small-sized electronic devices.